Insights into the dynamics of evaporation and proton migration in protonated water clusters from Large-scale Born–Oppenheimer direct dynamics

Authors

  • Vladimir V. Rybkin,

    Corresponding author
    1. The Department of Chemistry, Centre for Theoretical and Computational Chemistry (CTCC), University of Oslo, Postboks 1033, Blindern 0315, Oslo, Norway
    • The Department of Chemistry, Centre for Theoretical and Computational Chemistry (CTCC), University of Oslo, Postboks 1033, Blindern 0315, Oslo, Norway

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  • Anton O. Simakov,

    1. The Department of Chemistry, Centre for Theoretical and Computational Chemistry (CTCC), University of Oslo, Postboks 1033, Blindern 0315, Oslo, Norway
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  • Vebjørn Bakken,

    1. The Department of Chemistry, Centre for Theoretical and Computational Chemistry (CTCC), University of Oslo, Postboks 1033, Blindern 0315, Oslo, Norway
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  • Simen Reine,

    1. The Department of Chemistry, Centre for Theoretical and Computational Chemistry (CTCC), University of Oslo, Postboks 1033, Blindern 0315, Oslo, Norway
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  • Thomas Kjærgaard,

    1. The Department of Chemistry, Centre for Theoretical and Computational Chemistry (CTCC), University of Oslo, Postboks 1033, Blindern 0315, Oslo, Norway
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  • Trygve Helgaker,

    1. The Department of Chemistry, Centre for Theoretical and Computational Chemistry (CTCC), University of Oslo, Postboks 1033, Blindern 0315, Oslo, Norway
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  • Einar Uggerud

    Corresponding author
    1. The Department of Chemistry, Centre for Theoretical and Computational Chemistry (CTCC), University of Oslo, Postboks 1033, Blindern 0315, Oslo, Norway
    • The Department of Chemistry, Centre for Theoretical and Computational Chemistry (CTCC), University of Oslo, Postboks 1033, Blindern 0315, Oslo, Norway

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Abstract

Large-scale on-the-fly Born–Oppenheimer molecular dynamics simulations using recent advances in linear scaling electronic structure theory and trajectory integration techniques have been performed for protonated water clusters around the magic number (H2O)nH+, for n = 20 and 21. Besides demonstrating the feasibility and efficiency of the computational approach, the calculations reveal interesting dynamical details. Elimination of water molecules is found to be fast for both cluster sizes but rather insensitive to the initial geometry. The water molecules released acquire velocities compatible with thermal energies. The proton solvation shell changes between the well-known Eigen and Zundel motifs and is characterized by specific low-frequency vibrational modes, which have been quantified. The proton transfer mechanism largely resembles that of bulk water but one interesting variation was observed. © 2012 Wiley Periodicals, Inc.

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